The aim of our study was to determine whether there is a relationship of flow through arteriovenous fistula and adequacy of dialysis in patients treated with repeated hemodialysis. The study included 37 patients who were on the program of repeated hemodialysis for more than three months. Patients were divided into two groups according to the flow through the arteriovenous fistula. For each patient, the observed parameters were recorded at baseline and after six months. In both phases of the study, more patients who had reduced flow through the fistula had inadequate dialysis but none of these differences reached statistical significance. The frequency of abnormal values of laboratory parameters was higher in patients who had reduced flow through the fistula, but these differences were not significant in the first phase of the study. Between the two phases of the study in patients with adequate flow through the fistula, there was a reduction in the frequency of pathological values of laboratory parameters, and in the group of the patients with reduced flow rate the frequences remained the same or increased, so that in the second phase of the study the incidence of hypocalcemia was significantly higher in patients with low flow. Satisfactory flow through the vascular access is important, but not decisive factor for good dialysis adequacy and must be viewed within the context of other clinical and laboratory parameters.